There are three major problems confronting the fractionation industry. One problem is that of maldistribution of liquid across a contact tray, outlined in some detail in Canadian Patent No. 949,444, issued June 18, 1974 and entitled LIQUID-GAS CONTACT TRAY (Matsch). A major cause of maldistributions, and hence uneven vapor/liquid contact is the varying cross-section of liquid across such contact tray. This varying cross-section causes an ineffective bubble area on the side or sides of the contact tray termed by some authors as "end wastage area". This phrase has been used by Professor Matthew Van Winkle of the University of Texas, Chemical Engineering Department, in his text entitled "Distillation", see page 574, published by McGraw-Hill, 1967. This is a continually occurring problem in round columns, and such problem can be eliminated by employing an effectively rectangular contact tray as is taught in the inventors' co-pending patent application, Ser. No. 840,134, filed Mar. 17, 1986 and entitled VAPOR/LIQUID CONTACT COLUMN STRUCTURE, now U.S. Pat. No. 4,750,975, issued June 14, 1988. This co-pending patent application also teaches the imperical reasons for employment of essentially rectangular vapor/liquid contact trays wherein fluid flow is uniform and unidirectional over the plate.
A second problem presently confronting the industry is the magnitude of the vapor-pressure drop across a contact tray; the greater the drop, the greater the summation of pressure drops over the height of the column and hence the greater the energy requirement to force the vapors upwardly through the contact trays. The present invention substantially reduces vapor pressure drop across individual trays by means of employment of kinetic energy of fluid flowing over submerged baffles arranged mutually parallel and transverse to fluid flow.
A third problem of the industry is achieving effective uniform contact between the liquid and vapor at the tray. More contacts between liquid and vapor, where the heat transfer or mass transfer takes place, increases efficiency and reduces energy consumption. With the employment of submerged baffles or weirs, there is effected a greater contact of liquid and vapor which creates more heat transfer thereat and is more efficient.